JP3559930B2 - Information playback device - Google Patents

Description

  The present invention relates to an apparatus for reproducing an information signal such as a digital audio signal from a disk.

  In recent years, digital audio devices using optical disks have been developed. As a reproduction-only system, a compact disk (hereinafter, referred to as "CD") player is well known, and as a recordable system, there is a write-once optical disk system which can be written only once. Further, a magneto-optical type optical disk system capable of recording any number of times is being developed. As an example, there is a mini disk (MD) system disclosed in Non-Patent Document 1. The MD system records and reproduces an audio signal that is data-compressed on a disk by a magneto-optical method. A guide groove for tracking control is formed on the disk in advance, and the guide groove is continuous with the entire circumference of the disk. The address information attached is recorded. Therefore, the search can be performed regardless of the presence or absence of the recording signal.

  FIG. 20 is a block circuit diagram of the MD system. In the figure, 101 is a two-channel audio input terminal, 102 is an analog / digital conversion circuit (A / D converter), 103 is an encoder, 104 is a recording memory, and 105 is a recording signal processing for adding an error correction code and modulating a signal. Circuit, a clock generation circuit for generating and supplying a clock required for each circuit of the system; 107, a recording head driving circuit; 108, a recording magnetic head; 1, a disk; 2, an optical pickup; 3, a reproduction amplifier; A reproduction signal processing circuit for demodulation and error correction, 16 is a buffer memory, 17 is a decoder, 7 is a digital / analog conversion circuit (D / A converter), 8 is a two-channel audio output terminal, 18 is an address decoder, and 11 is a microcontroller. Computer, 12 is a servo circuit, 13 is a disk motor, 14 is a key input, 5 is a display circuit.

  FIG. 21 is a timing chart of signal processing during recording and reproduction. The operation will be described with reference to FIGS. At the time of recording, the analog audio signal supplied to the audio input terminal 101 is sampled by the A / D converter 102 and converted into a digital signal. This digital audio signal is compression-coded by the encoder 103 and reduced to about 1/5 of the original information amount.

  The compressed signal is temporarily stored in the recording memory 104, and is read out intermittently at the same rate as before compression as shown in FIG. By intermittently reading, the difference between the data writing rate to the memory and the reading rate from the memory is absorbed. The recording signal processing circuit 105 performs an interleaving process for rearranging the signal order in order to disperse errors during reproduction, generates and adds an error correction code, and modulates the signal. This modulated signal is magneto-optically recorded on the disk 1 from the recording magnetic head 108 via the recording head drive circuit 107. The recording operation is performed in response to the intermittently supplied modulated signal (FIG. 21 (c)). As shown in FIG. 21 (d), the signal recording operation and the recording pause are alternately repeated to perform the recording. Before performing the search, the last address of the part recorded so far is searched, and the data is continuously recorded.

  At the time of reproduction, light is emitted from the optical pickup 2 to the disk 1, and a signal written on the disk 1 is read by the reflected light. This optical information is converted into an electric signal by the optical pickup 2 and supplied to the reproducing amplifier 3. The signal amplified by the reproduction amplifier 3 is supplied to a reproduction signal processing circuit 6, where it is demodulated by a method such as EFM (Eight to Fourteen Modulation), error detection and correction processing, and deinterleaving processing for restoring the order of the signals. Is output to the buffer memory 16.

  On the other hand, the output of the reproduction amplifier 3 is also supplied to the address decoder 18. The address decoder 18 reproduces an address signal continuously attached to the entire circumference of the disk, in order to take out address information contained in a guide groove of a light spot previously engraved on the disk 1. The tracking information is obtained by detecting wobbling. This tracking information is supplied to a servo circuit 12, where a tracking servo is applied so that the optical pickup 2 scans a predetermined guide groove, and the rotation of the disk 1 is kept constant at a constant linear velocity so that the waviness of the guide groove is constant. And the disk motor 13 is controlled.

  The reading of the signal from the disk 1 is performed intermittently in the same manner as the writing at the time of recording, and the reproduction operation and the reproduction pause state are alternately repeated as shown in FIGS. Is supplied to a decoder 17, the audio signal restored to the information amount before compression is converted into an analog signal by a D / A converter 7, and then output from an audio output terminal 8. The microcomputer 11 receives an address signal engraved in a disc guide groove from an address decoder 18 and an address signal recorded corresponding to an audio signal, and further receives a key input 14 from the outside, and Control. Also, the display circuit 15 is driven to display information such as the operation mode of the system and the elapsed playback time.

  In this system, the optical pickup 2 reads a signal from the disk 1 at a rate of about 1.4 Mbit / sec (Mbps). On the other hand, since the input rate to the decompression circuit 17 is about 0.3 Mbps, when the buffer memory 16 of 1 Mbit is used, the buffer memory 16 becomes full when reading from the disk for about 0.9 seconds. Also, about 3 seconds of reproduction can be performed with the full buffer memory 16 of compressed data. For this reason, even when the optical pickup 2 jumps due to a disturbance, for example, the sound is not interrupted immediately because the data is held in the buffer memory 16, and the position immediately before the jump before the signal in the buffer memory 16 disappears disappears. By searching and writing the signal to the buffer memory 16, continuous reproduction without sound interruption can be performed.

  Further, as an information reproducing apparatus in which a plurality of discs are loaded into the apparatus and one of them is selected and reproduced, there is an in-car or stationary magazine type changer CD player. FIG. 22 is a block circuit diagram of a conventional magazine type changer CD player. Six to ten CDs are loaded into one magazine, and the magazine is mounted on the changer mechanism 100 of the player. Thereafter, the CD specified by the user is pulled out of the magazine, mounted on a disk mechanism (not shown), and reproduced. Therefore, when a user performs a key operation of a disk change to play another disk while playing a certain disk, first stop the rotation of the currently playing disk and then store it in the magazine, and then A designated another disk is pulled out of the magazine, mounted on a disk mechanism and rotated to start a reproducing operation.

When a disc is exchanged in such a changer type information reproducing apparatus, the following processing must be performed from the end of the reproduction of the disk to the reproduction of the next disk, which takes a considerable amount of time. .
1. Stop disk rotation.
2. The disc that has been played is stored in the magazine.
3. Next, the disc to be played is taken out of the magazine.
4. Insert a disc.
5. Spin the disc.
6. Read TOC (Table Of Contents) information.

  Usually, a CD often includes a silent portion of about 2 to 3 seconds at the end of the program, and about 2 to 3 seconds from the end of the program until the processing as described above is started. As a result, the time of silence at the time of disc replacement is further increased.

As described above, the time required for a disc change takes at least several seconds, and during this time a silence state in which no reproduced sound is output continues. There was a limit. Therefore, an example of eliminating a silent time by using a memory is disclosed in Japanese Patent Application Laid-Open No. Hei 3-273586. In this apparatus, a signal is read from a CD at a speed higher than the reproduction speed and stored in a memory, and the signal is read from the memory at a predetermined reproduction speed. Then, during the silent time of the disk change, the signal stored in the memory is continuously read to substantially eliminate the silent time.
Nikkei Electronics December 9, 1991 p. 160 to p. Article 168, "Realizing with Minidisc, Magneto-optical Recording and Data Compression Technology"

  Since the conventional MD system is configured as described above, if the optical pickup 2 causes a track shift due to an impact when the data in the buffer memory 16 is small during reproduction, the data in the buffer memory 16 immediately becomes empty. , The sound may be interrupted. Further, since the data is delayed in the buffer memory 16, if the address or the time information reproduced by the optical pickup 2 is displayed as it is, the data different from the data corresponding to the data output from the terminal 8 is displayed. Become.

  Furthermore, in the conventional changer type information reproducing apparatus, when a plurality of CDs are reproduced in a predetermined order and in a predetermined music order, silence time can be eliminated or shortened. However, when the user forcibly designates a disc change during reproduction, there is no problem that the effect of reducing the silence time is completely absent since the necessary signals are not stored in the memory.

  SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and shortens the time from the end of reproduction of a program on one disk to the start of reproduction of a program on the next disk. It is an object of the present invention to provide a disc reproducing apparatus capable of performing the above.

  It is another object of the present invention to provide a system in which the capacity of the memory is effectively used and the sound is not interrupted as much as possible, even if a track shift occurs due to vibration.

  It is another object of the present invention to provide a changer type disk device in which a silent time generated when a disk is replaced is short.

  It is another object of the present invention to provide an information reproducing apparatus which performs display by correcting the reproduced address or time information so as to correspond to a signal output.

  Also, by greatly reducing or eliminating silence time during a disc change, an information reproducing apparatus that can be used in the same sense as reproducing a single disc even when reproducing a plurality of discs. It is an object of the present invention to provide an information reproducing apparatus which can reduce a silent time even when a user forcibly specifies a disc change.

  It is another object of the present invention to provide an information reproducing apparatus with good operability that allows the user to know the contents of another disk while playing back a certain disk, or to check the contents of all disks by ear.

  An information reproducing apparatus according to a first aspect of the present invention includes a partial information memory for storing a head portion of information to be reproduced of each of a plurality of recording media, and a medium for outputting information of a head portion of a recording medium to be reproduced next. Control means for terminating the change, reading the information following the head portion from the recording medium to be newly reproduced, and outputting the information continuously to the information of the head portion.

  In the information reproducing apparatus of the first invention, the information of the first part of the reproduction target information of the plurality of recording media, for example, the head of the first tune in the case of music information is stored in the partial information memory, When a change command is issued, the information of the head portion of the recording medium to be reproduced next is read out from the partial information memory and output, and during the output period, the medium change is completed and the information following the head portion from the new recording medium is read. The information is read out and output continuously to the information of the head portion, and the silent time generated when the medium is changed is reduced as much as possible.

  An information reproducing apparatus according to a second aspect of the present invention includes a partial information memory that stores a part of the recording information of each of a plurality of recording media as partial information, and a unit that selectively reads and reproduces and outputs the partial information of a specified recording medium. And characterized in that:

  In the information reproducing apparatus according to the second invention, a part of the record information capable of grasping the record contents of the record information of the plurality of record media is stored in the partial information memory as the partial information, and the information of the designated record medium is recorded. Partial information is selectively read from the partial information memory, reproduced and output, and the contents of the recording medium can be grasped without actually driving the recording medium.

  An information reproducing apparatus according to a third aspect of the present invention includes a partial information memory that stores a part of the recording information of each of a plurality of recording media as partial information, and a unit that selectively reads and reproduces and outputs the partial information of a specified recording medium. An auxiliary power supply for backing up the information stored in the partial information memory so that the information stored in the partial information memory does not disappear when the power supply of the apparatus is cut off, a unit for detecting that a new recording medium has been replaced even while the power supply of the apparatus is cut off, Means for storing information of a part of the recording medium newly added by replacement in a partial memory.

  In the information reproducing apparatus of the third invention, a part of the recording information which can specify the recording contents of the recording information of the plurality of recording media is stored in the partial information memory as the partial information, and the designated recording is performed. The partial information of the medium is selectively read out from the partial information memory and reproduced and output, and the replacement of the recording medium is detected even when the power supply of the apparatus is cut off, and the partial information of the recording medium newly added by the replacement is stored in the partial information memory. The contents are stored, and the contents of the recording medium can be grasped without actually driving the recording medium.

  Since the information reproducing apparatus according to the present invention can specify the minimum amount of data to be stored in the memory, it is possible to set the maximum time during which a normal sound can be produced even if the pickup shifts the track due to vibration. it can.

  In addition, since the writing and reading cycles to and from the memory can be changed according to the minimum amount of data stored in the memory, a large cycle can be set so as to be convenient for performing the reproduction signal processing of another system.

  Further, in the disc changer type information reproducing system, the amount of data stored in the memory can be controlled to be maximum when the disc is replaced, so that the silent time when the disc is replaced can be reduced.

  In addition, the reproduced address or time information is corrected and displayed using the difference between the write address and the read address of the memory, so that a display corresponding to the data output from the memory can be performed and a time lag is not felt.

  Also, when ending the reproduction of a program, the end of the program of the disc is detected from the output level of the signal immediately before the end of the program, and the disc is stopped immediately. If the system is applied to a system for exchanging disks, the time of silence at the time of exchanging disks can be shortened, and disk exchange can be performed smoothly.

  In addition, since the playback program is temporarily stored in the buffer memory, the disc can be stopped before the playback of the program ends, and if this is applied to a system for automatically exchanging a plurality of discs, The time of silence at the time of replacement can be shortened, and the replacement of the disk can be performed smoothly.

  In addition, the reproduction program is temporarily stored in the buffer memory, the end of the program of the disc is detected from the output level of the signal immediately before the end of the program, and the disc is stopped immediately, so that the reproduction of the program ends. If the disk can be stopped beforehand and this is applied to a system for automatically replacing a plurality of disks, the time of silence at the time of disk replacement can be reduced, and the disk replacement can be performed smoothly.

  In addition, the head portion of the first song of a plurality of discs is reproduced in advance and stored in the storage means, and when a key operation for disc change is performed, the head portion corresponding to the disc to be reproduced next is stored. Means that the disc change is completed during that period, and a position on the disc that is continuous with the output signal from the storage means is searched and reproduced so as to be continuous with the output from the storage means. A disk reproducing apparatus with excellent operability, which can substantially eliminate a silent state accompanying a disk change even when a disk change is performed during the disk change.

  In addition, each of the head portions of the first song of the plurality of discs is played back and stored in the storage means, and the plurality of head portions are continuously played back from the storage means in response to a key operation, or a portion is read from the storage means. Plays the beginning of the song, so you can know the contents of other discs while playing a certain disc, or you can check the contents of all discs by ear. A device is obtained.

  Further, the head portions of the top songs of the plurality of discs are reproduced in advance and stored in the storage means, and the plurality of head portions are continuously reproduced from the storage means in response to a key operation, or the head portions are read from the storage means. Reproduce the beginning of the song of the part, confirm that the discs have been replaced by the disc detection means even while the power is off, and play back the beginning of the top song only for the replaced disc and store it in the storage means. Since the signal is stored and held as a signal to be reproduced, there is no waiting time for the user after turning on the main power when there is no disc change, and there is little waiting time for the user even when only some of the discs are changed. Despite this, it is possible to virtually eliminate the silence caused by a disc change, and to know the contents of other discs or the contents of all discs. Excellent disc reproducing apparatus can be obtained.

Embodiment 1 FIG.
Hereinafter, an information reproducing apparatus according to the present invention will be described with reference to the drawings. The same or corresponding parts as those in the conventional example are denoted by the same reference numerals, and description thereof will be omitted. FIG. 1 is a block circuit diagram of the first embodiment, in which the recording system is omitted and only the reproducing system is shown. In the figure, 16 is a buffer memory, 31 is a circuit for generating a write address of the buffer memory 16, 32 is a circuit for generating a read address of the buffer memory 16, 33 is a selector, 34 is a write flag generation circuit, A write flag is generated from the difference between the write addresses 31a and the reference value input from the terminal. A write control circuit 35 controls writing to the buffer memory 16 by controlling a clock to the write address generation circuit 31 and a write pulse 35a to the buffer memory 16.

FIG. 2 is a memory map showing the relationship between the amount of data stored in a memory having an m-bit address and the write and read addresses, where W indicates data being written, and R indicates data being read. The write address and the read address circulate from address 0 to 2 ^m -1 of the buffer memory 16 while counting up. FIG. 2A shows the case where the write address is larger than the read address, and the shaded area indicates the amount of data stored in the buffer memory 16. The wider the shaded area, the longer the reproduction time from the stop of writing. Can be taken for a long time. FIG. 2B shows a case where the address further advances from FIG. 2A and the address of W returns to 0, and further counts up, and R becomes an address larger than W.

Next, the operation will be described. The data corrected by the reproduction signal processing circuit 6 is intermittently written to the buffer memory 16 based on the write address generated by the write address generation circuit 31. When writing, the data is written at a rate of 1.4 Mbps. On the other hand, the data stored in the buffer memory 16 is continuously read at 0.3 Mbps based on the address generated by the read address generation circuit 32. The write flag generation circuit 34 calculates the amount of data remaining in the buffer memory 16 from the difference between the write address 31a and the read address 32a, and calculates the calculated data amount to be equal to or less than the first reference value E input from the terminal 36. When this happens, the write flag is set to "0" (writable), and when the calculated data amount becomes equal to or larger than the second reference value F previously selected from the address maximum value "2 ^m " or a value smaller than 2 ^m near the address, the write flag is set. It is set to “1” (write prohibited).

  When the write flag is “0”, the write control circuit 35 controls the write address generation circuit 31 to generate an address for writing data reproduced from the disk 1 to the buffer memory 16, and writes the data to the buffer memory 16. The pulse 35a is output. When the write flag is "1", the supply of the clock to the write address generation circuit 31 is stopped so that the write address is not updated, and the supply of the write clock to the buffer memory 16 is stopped.

  As described above, when the amount of data in the buffer memory 16 decreases below the first reference value E, the buffer memory 16 writes data, and the second reference value F indicating immediately before the amount of data in the buffer memory 16 overflows. , Writing is prohibited until the amount of data in the buffer memory 16 decreases to E again.

  FIG. 3 is a diagram showing a change in the amount of data in the buffer memory 16, in which the horizontal axis represents time and the vertical axis represents the amount of data in the buffer memory 16, and FIG. FIG. 3B shows an example in which the value E is large, and FIG. 3B shows an example in which the value E is small. In the case of FIG. 3A, a large amount of data is always stored in the buffer memory 16, which is advantageous for vibration. In addition, in the case of FIG. 3B, since the write prohibition period is long, this period can be used for reproduction of another system. The value of the first reference value E is set from the terminal 36 according to the application.

  When the optical pickup 2 causes a track shift, the address decoder 18 detects this and outputs it to the write control circuit 35. In the case of a track shift, the write control circuit 35 inhibits writing until the address returns to normal even if the data amount in the buffer memory 16 becomes equal to or less than E.

FIG. 4 is a block circuit diagram showing an example of the configuration of the write flag generation circuit 34. A subtractor 40 subtracts the read address value 32a from the write address value 31a, and 41 determines the polarity of the output of the subtracter 40. A polarity determinator that outputs “0” for plus and “2 ^m ” for minus, 42 is an adder, 43 is a comparator for determining the magnitude of the output of the adder 42 with respect to the reference value, and a subtractor 40 , A polarity determiner 41 and an adder 42 constitute an arithmetic unit 44 for calculating the amount of data remaining in the buffer memory 16.

In the case of FIG. 2A, since the output of the subtractor 40 is positive, the output of the adder 42 is the same as the output of the subtractor 40. In the case of FIG. 2B, since the output of the subtractor 40 is negative, “2 ^m ” is added to the value of the subtractor 40 by the adder 42 and output. As described above, the polarity determiner 41 outputs a data amount remaining in the hatched portion of FIG. 2 as a positive value. The comparator 43 outputs "1" when the output of the adder 42 becomes smaller than the first reference value E, and when the output of the adder 42 reaches the predetermined second reference value F of about 2 ^m , the buffer memory 16 overflows. In order to prevent the writing, "0" is output and the writing control circuit 35 controls the writing to be prohibited.

Embodiment 2 FIG.
FIG. 5 is a block circuit diagram showing an information reproducing apparatus according to a second embodiment of the present invention. Reference numeral 50 denotes sub-information for extracting position information on the disk or time information corresponding to the elapsed playing time from a signal reproduced from the disk 1. It is an extraction circuit. The second embodiment is a changer type system in which a plurality of discs 1 are stored in a magazine and all discs can be continuously played back or a program can be selectively played back. Is completed, the disc is automatically replaced with the next disc and the reproduction is continued, but a silence time of about 10 to 15 seconds occurs when the disc is replaced.

  When a 1 Mbit RAM is used for the buffer memory 16, a compressed signal equivalent to 3 seconds as a reproduction time is stored in the memory in the MD system. Therefore, when a 4 Mbit memory is used, a compressed signal equivalent to 12 seconds can be stored. it can. In the second embodiment, this is used to reduce the silent time during a disc change.

Next, the operation will be described.
The key input 14 designates continuous playback or program playback. In the case of program playback, the disc number and station number of the music to be played are also designated. These designations are stored in an internal memory (not shown) of the microcomputer 11, and the microcomputer 11 uses the address or time information indicating the position on the disc extracted by the sub-information extraction circuit 50 to reproduce the disc being reproduced. It is determined whether or not the last tune to be completed has been completed. The last song is the last song of the disc in the case of continuous reproduction, and the last programmed song in the disc in the case of program reproduction. By reading the TOC information recorded on a part of the disc, the start and end positions of each song or time information can be obtained.

  When the microcomputer 11 determines that the music has ended, it sets the write stop signal 11b to the stop mode, outputs the signal to the write control circuit 35, and prohibits the writing of the reproduction signal to the buffer memory 16. In the prohibited state, the write address is not updated, and the write clock supplied to the buffer memory 16 is not output.

  Next, when the disk 9 is replaced and the demodulated signal is normally reproduced, the reproduced signal processing circuit 6 outputs the demodulated OK signal 6a. When detecting this signal, the microcomputer 11 sets the write stop signal 11b to the release mode. The write control circuit 35 updates the address again and writes the new song on the disk 1 to the buffer memory 16, and the last song on the previous disk 1 and the first song on the new disk 1 are almost continuous in the buffer memory 16. Since the disk is stored, the silent time at the time of disk replacement is reduced.

  By changing the capacity of the buffer memory 16, it is possible to arbitrarily select the time to be absorbed by the delay of the output with respect to the input to the buffer memory 16. However, if a memory having an excessively large capacity is used, the time for absorption becomes long, so that when only one disc is reproduced, a sound is produced even after the reproduction of the disc 1 is stopped, giving a sense of incongruity. Therefore, when a large-capacity memory is used, the first reference value E is increased to increase a large amount of data as shown in FIG. 3 (a) only when it is programmed to reproduce the next disk. Should be stored in the buffer memory 16. However, when the system is placed in another room to listen to the sound, the first reference value E may always be kept high.

Embodiment 3 FIG.
FIG. 6 is a block circuit diagram showing a third embodiment of the information reproducing apparatus according to the present invention. Reference numeral 51 denotes a register for holding the output of the address decoder 18; 44 is an address correction circuit for correcting using the output of FIG.

  As described above, as the capacity of the buffer memory 16 is increased, the delay time in the buffer memory 16 increases. For this reason, when the microcomputer 11 converts the address data extracted by the address decoder 18 into time data and displays it, the deviation between the music output from the output terminal 8 and the displayed time information increases. For example, if a delay of up to 12 seconds occurs using a 4 Mbit memory, when it is displayed that 12 seconds have passed since the performance was changed to track number 2, the music of track number 2 was transferred to terminal 8 Will start to be output.

  The third embodiment solves such an inconvenience, and the register 51 latches an address output from the address decoder 18. While writing to the buffer memory 16 is performed, the register 51 is updated, but is not updated while writing is prohibited. Therefore, the address of the register 51 is the latest data written to the buffer memory 16, and it can be said that the address corresponds to the write address or the position information of the data stored at the designated address.

  On the other hand, the output of the arithmetic unit 44 of the write flag generation circuit 34 is the difference between the read address and the write address. This is converted into an address difference on the disk 1 by an address correction circuit 52. Since the amount of data contained in one address is constant, this conversion can be easily calculated. Then, the address correction circuit 52 outputs an address obtained by subtracting the obtained address difference from the address of the register 51 to the microcomputer 11. The microcomputer 11 converts this into time and displays it. Since the address output from the address correction circuit 52 corresponds to the address of the data read from the buffer memory 16, there is no difference between the actual playing elapsed time of the music being reproduced and the display time.

  Since the delay time in the reproduction signal processing circuit 6 and the decompression circuit 17 is a value that can normally be ignored without any problem, there is no problem as long as the delay time in the buffer memory 16 is corrected. When obtaining the time from the address reproduced from the disk 1, the microcomputer 11 converts the address into time information and displays it.

  In the second embodiment, the output of the sub-information extraction circuit 50 is used to determine the end of the music. However, the same effect can be obtained by using the output of the address decoder 18.

  In the third embodiment, the output of the address decoder 18 is used for correcting the address. However, the same effect can be obtained by using the sub-information extraction circuit 50 shown in FIG. 5 and using this output.

  Further, in each of Embodiments 1 to 3, the second reference value F is a fixed value, but may be arbitrarily set from outside similarly to the first reference value E.

  Further, in each of the first to third embodiments, an audio signal is used as an example. However, a similar effect can be obtained with a device that reproduces a digital signal.

Embodiment 4 FIG.
FIG. 7 is a diagram showing a configuration of an information reproducing apparatus according to a fourth embodiment of the present invention. In the figure, 1 to 5, 7 to 15 are the same as the conventional example shown in FIG. Reference numeral 20 denotes an end detection circuit for detecting the end of the program of the disc being reproduced.

  In the fourth embodiment, the time-series digital audio signal restored to the original signal by the signal processing circuit 5 is input to the end detection circuit 20. The end detection circuit 20 determines that the program is ended when the level of the reproduced information signal becomes lower than a predetermined level by the end time of the program of one disk.

  FIG. 8 shows a timing chart when the end of the program is detected. In the figure, (a) shows the reproduction signal level, (b) shows the operation mode of the conventional CD system, and (c) shows the operation mode of the fourth embodiment.

  It is already known that the program ends at time t3 due to the reproduction time of the music recorded in the TOC information of the CD, and the reproduction of the program ends at time t3 in the conventional CD system. Stop. However, in the embodiment according to the present invention, the end detection circuit 20 monitors the level of the reproduced signal for a predetermined time q seconds before the time t3 at which the program ends, and detects no sound or no sound for a predetermined time p seconds (p <q). If a signal whose level is very low and is below the level (audible limit) which cannot be heard continues, it is determined that there is no sound during the remaining times t2 to t3, and reading from the disk 1 is performed at time t2. Terminate and immediately stop the disk 1.

  By doing so, the time until the disk 1 stops can be reduced by s seconds as compared with the conventional CD system, and if this is applied to a system for automatically exchanging a plurality of disks, Since the time of silence at the time of disc exchange can be reduced, the time from the end of reproduction of the first disc to the start of reproduction of the next disc can be shortened.

Embodiment 5 FIG.
In the fifth embodiment, the time of silence at the time of disk exchange is further reduced by using the buffer memory of the MD system that temporarily stores the reproduced compressed information in the buffer memory, decompresses and outputs the compressed information. FIG. 9 is a diagram showing a configuration of the fifth embodiment. In the drawings, the same or corresponding parts as those in the conventional and the above-described embodiments are denoted by the same reference numerals, and description thereof will be omitted.

  Next, the operation will be described. A signal written on the disk 1 is read by the optical pickup 2, a signal sequence error is corrected by the signal processing circuit 5, and the signal sequence rearranged by the interleaving process is returned to the original sequence. The processing is the same as that of the conventional apparatus. As shown in FIG. 10, the buffer buffer memory 16 and the decompression circuit 17 temporarily store the intermittently input data, decompress the compressed data, and continuously convert the original time-series data under the control of the microcomputer 11. Output. That is, the signal sequence input to the buffer memory 16 between times t0 and t1 in the figure is continuously output between times t2 and t4. Similarly, the signal sequences input during times t2 to t3, t4 to t5, and t6 to t7 are continuously output during times t4 to t6, t6 to t8, and t8 to t10, respectively. Between times t1 to t2, t3 to t4, t5 to t6, and t7 to t8 (shaded portions in the drawing), the writing to the buffer memory 16 is stopped.

  The signal restored to the original continuous time-series data in this way passes through a D / A converter 7, outputs an analog audio signal from an analog audio output terminal 8, passes through a digital output circuit 9, and outputs a digital audio interface signal. Is output from the digital audio output terminal 10. The microcomputer 11 performs various controls of the servo circuit 12 and the signal processing circuit 5 based on the reproduced additional information and the key input 14, and also displays information such as the operation mode and time of the system via the display circuit 15 via the display circuit 15. To be displayed.

  In the fifth embodiment, the disk is stopped before the end of the reproduction signal by using the buffer memory 16 as in the second embodiment, but the silence time is further shortened compared to the second embodiment. FIG. 11 shows a timing chart at the end of the program. In the figure, (a) is a conventional CD reproduction output, (b) is a disk read timing of the second embodiment, (c) is a reproduction output of the second embodiment, and (d) is a disk read of the fifth embodiment. The timing (e) shows the reproduction output of the fifth embodiment.

  In the conventional CD system, as shown in FIG. 11A, the reproduction of the program ends at time t5, the disk is stopped here, the disk is replaced, and the reproduction starts at time t11. Therefore, there is no sound for the time k seconds required for disc replacement. However, in the second embodiment using the buffer memory 16, reading from the disk 1 is completed at time t3 as shown in FIGS. 11B and 11C, and the buffer memory 16 is controlled by the microcomputer 11. The writing to the disk 1 is completed, the disk 1 is stopped, the disk exchange is started, and the reading from the next disk 1 is restarted at time t6. In this case, since the reproduction information signal is temporarily held in the buffer memory 16, the continuous time-series reproduction output continues until time t5, and the reproduction output starts again at time t9. Assuming that the time k seconds does not change, in the case of the fifth embodiment, the silence time is kh seconds, which is reduced by h seconds.

  Further, in the fifth embodiment, the following operation can be performed. That is, in the fifth embodiment, when the reproduction of the disk 1 is restarted, as shown in FIGS. 11D and 11E, the data read first from the disk 1 is immediately decompressed and output. When the microcomputer 11 controls so that the reading is performed from the second time as in the related art, the silence time is further reduced by i seconds as compared with the second embodiment. That is, as shown in FIGS. 11 (d) and 11 (e), the data read from the disk 1 at times t6 to t7 is immediately decompressed and output between times t7 and t10, and at times t7 to t8. The read data is output after time t10. By doing so, the silence time is further reduced by i seconds to khi-seconds. In FIG. 11, a hatched portion is a silent portion.

Embodiment 6 FIG.
FIG. 12 is a block circuit diagram of Embodiment 6 of the information reproducing apparatus of the present invention. Note that the same or corresponding parts as in the conventional example and the above-described embodiment are denoted by the same reference numerals, and description thereof will be omitted. In the sixth embodiment, an end detection circuit 20 similar to that of the fourth embodiment is added to an MD system using a buffer memory for temporarily storing compressed data. The time-series digital audio signal restored to the original signal by the signal processing circuit 5 is input to the end detection circuit 20. The end detection circuit 20 determines that the program has ended when the level of the reproduced information signal becomes lower than a predetermined level within the end time of the program of one disk.

  FIG. 13 shows a timing chart when the end of the program is detected. In the figure, (a) is the reproduction signal level, (b) is the reproduction output of the conventional CD, (c) is the disk read timing of the sixth embodiment, (d) is the reproduction output of the sixth embodiment, and (e). Indicates the reproduction output of the seventh embodiment.

  It is already known that the program ends at time t6 due to the reproduction time of the music recorded in the TOC information of a CD or the like, and the reproduction of the program ends at time t6 in the conventional CD system. Is stopped, and after the disk is replaced, reproduction is started at time t11. Thus, during the time k seconds required for disc replacement, there is no sound (hatched portion Y), and a signal at the end of the program or a signal whose level is too low to be heard (audible limit) is reproduced for h seconds. (Hatched portion X), there is a silence portion of substantially h + k seconds.

  However, in the sixth embodiment using the buffer memory 16 and the end detection circuit 20, the level of the reproduced signal for a predetermined time q seconds before the time t6 at which the program ends is monitored, and a predetermined time p seconds (p <Q), i.e., between times t3 and t4, when no sound or a signal whose level is extremely low and cannot be heard is continuous below an audible limit, all silence is also performed during the remaining times t4 and t6. Then, the reading of the compressed data from the disk 1 is terminated at time t2, the disk 1 is immediately stopped, the disk exchange is started, and the reading from the next disk 1 is restarted at time t7. In this case, since the reproduction information signal is temporarily held in the buffer memory 16, the continuous time-series reproduction output continues until time t5, and the reproduction output starts again at time t9. Assuming that the time k seconds does not change, in the case of the sixth embodiment, the time during which silence is reproduced is reduced by i seconds to be h + ki. In FIG. 13, a hatched portion X is a playback output but can be regarded as a silent portion, and a hatched portion Y is a silent portion due to disc replacement or the like.

Embodiment 7 FIG.
Further, as shown in FIG. 13 (e), when the reproduction of the disc is resumed, the data read from the disc 1 first is immediately decompressed and output. Is further reduced by j seconds to h + kij seconds.

  In the fourth to seventh embodiments, the level of the reproduction signal is used to detect silence or low-level sound. However, in order to determine the level of the reproduction signal, for example, the range of the reproduction signal such as a scale factor is used. May be used.

  Further, in the fourth to seventh embodiments, the reading from the disc 1 is terminated when the signal becomes silent or the signal is very low and the signal is below the level (audible limit) which cannot be heard. The level may be a predetermined level. In this case, information after the reading from the disc 1 is terminated is obtained by approximating the reproduced signal as shown in FIG. Is also good.

Embodiment 8 FIG.
FIG. 15 is a block circuit diagram of a changer type information reproducing apparatus according to an eighth embodiment of the present invention. In the figure, the same or corresponding parts as those in the conventional example or the above-described embodiment are denoted by the same reference numerals, and description thereof will be omitted. In the figure, 19 is a low-pass filter (LPF), 21 is an error correction circuit, 22 is a memory data input / output circuit, 23 is a first memory, 24 is an address control circuit of the first memory, 25 is a second memory, 26 is an address control circuit of the second memory. As in the prior art, the reproduced signal demodulated by the demodulation circuit 4 is input to an error control circuit 21, where error detection and correction processing is performed, and deinterleaving processing for returning the order of the interleaved signal to the original state is performed. Done. The reproduction signal subjected to this processing is written to the first memory 23 through the memory data input / output circuit 22 under the control of the address control circuit 24. The reproduction signal once stored in the memory 23 is read out and supplied to the decoder 17 via the memory data input / output circuit 22.

  Writing of a signal to the first memory 23 is performed at a higher speed than reading from the first memory 23. That is, since the reading speed of the signal from the disk 1 is higher than the transfer speed of the output from the first memory 23, the signal amount in the first memory 23 increases. When the amount of signals in the memory 23 reaches a predetermined amount (a set overflow amount), the memory data input / output circuit 22 stops writing signals to the memory 23. At the same time, the microcomputer 11 stores the position information on the disk at that time and controls the servo control circuit 12 to repeatedly search the position. In the meantime, signal reading from the first memory 23 is sequentially continued at a constant speed. When the signal amount in the memory reaches a predetermined amount (a set amount of underflow), the memory data input / output circuit 22 outputs a signal. To resume. Therefore, the first memory 23 holds at least a signal equal to or larger than the set amount of underflow. For this reason, even if the optical pickup 2 jumps due to disturbance or the like and cannot scan a predetermined track, and the signal writing to the first memory 23 is stopped, the signal already held is continuously read and the jump is performed during that time. When the optical pickup 2 is returned by searching for a reproduction position immediately before the reproduction, a continuous output from the first memory 23 can be performed.

  When a disc is loaded into the information reproducing apparatus, the microcomputer 11 instructs the changer mechanism 100 to automatically pull out the discs one by one from the five discs and mount the discs on the disc mechanism. Playback of the loaded disc 1 is started in the same manner as during normal playback, but playback is performed for the first predetermined time of the first song of each disc, for example, 10 seconds. At this time, the signal read by the optical pickup 2 is supplied to the memory data input / output circuit 22 through the signal path described above, but is stored in the second memory 25 instead of the first memory 23. FIG. 16 is a conceptual diagram showing a data storage state of the second memory 25. The compressed signals for the first 10 seconds of the first song of each disk are stored in the areas 1 to 5 of the second memory 25, respectively. The correspondence between the disk number and the area on the memory is managed by the microcomputer 11.

  Next, an operation when a user performs a disc change operation during reproduction of a certain disc will be considered. FIG. 17 is a control flowchart for explaining the operation at this time. First, when a disc change instruction is input by the key input 14 (S1), the microcomputer 11 mutes the audio output of the disc being reproduced (S2), and simultaneously stops the disc rotation and causes the changer mechanism 100 to change the disc. And a disk change is started (S3). Next, a command is issued to the memory address control circuit 26 so as to read out from the memory a signal in the second memory 25 corresponding to the disk to be reproduced next designated by the key input 14, and the memory address control circuit 26 , And a signal for the first 10 seconds of the first song of the corresponding disc is selected and read (S4). At this time, the memory data input / output circuit 22 selects a signal so as to supply a signal read from the second memory 25 instead of the first memory 23 to the decoder 17. The signal restored by the decoder 17 is output from the audio output terminal 8 via the D / A converter 7 and the LPF 19, and from the digital audio output terminal 10 via the digital output circuit 9, and the mute is released (S5).

  At this time, since the signal output from the second memory 25 is obtained by compressing the audio signal for 10 seconds, the audio reproduction for the first 10 seconds of the first music can be performed. During this time, the changer mechanism 100 performs a disc change, and if a disc to be reproduced is loaded, a high-speed search is performed for the position of a signal that is continuous with the audio signal for the first 10 seconds of the first tune (S6). That is, since address information is recorded at predetermined intervals in the signal on the disk, the microcomputer 11 stores the last address of the signal first taken into the memory 25 and searches for the next address following the address. I do.

  Next, the optical pickup 2 reads a signal from the searched position, and the signal is stored in the first memory 23 in the same manner as in the above-described steady reproduction operation (S7). Also output during this time are signals stored in the second memory 25. After the corresponding last signal in the second memory 25 is output (S8), the memory data input / output circuit 22 is switched to output the signal from the first memory 23 (S9), and the memory address is output. The control circuit 24 controls the memory address so as to sequentially read the fetched signals. Therefore, during the first 10 seconds, the signal previously stored in the memory 25 is reproduced, and the signal from the disc can be reproduced without a break from the continuation of the signal.

Embodiment 9 FIG.
FIG. 18 is a flowchart illustrating the operation of the MD changer system according to the ninth embodiment. The block configuration of the system is the same as that of FIG. First, when a disk is loaded, the compressed signals for the first 10 seconds of the first song of each disk are stored in the areas 1 to 5 in the second memory 25 as described above.

  If the user wants to temporarily check the contents of another disc while playing a certain disc, the corresponding key is operated (S11), and the microcomputer 11 causes the corresponding area in the second memory 25 to be read. Is controlled to read out the signal. That is, for the memory data input / output circuit 22, the output signal is switched from the signal in the first memory 23 to the signal in the second memory 25 (S12). The second memory address control circuit 26 is instructed to read a signal in an area corresponding to a key operation among the areas 1 to 5 (S13). Then, after outputting the audio signal for 10 seconds (S14), the continuation of the disc that has been reproduced is reproduced again (S15).

  Next, for example, when the user wants to check the contents of all disks, the corresponding key is operated, and the microcomputer 11 sends a signal to be output to the memory data input / output circuit 22 at that time in the first memory 23. The signal is switched to the signal in the second memory 25. Then, it instructs the second memory address control circuit 26 to sequentially read the signals of the areas 1 to 5. The signal read out according to the memory address from the memory address control circuit 26 is supplied to the decoder 17 via the memory data input / output circuit 22, and the digital audio signal is restored. Therefore, as the audio output, the first 10 seconds of the first tune of each disc are sequentially reproduced. If the reproduction skip is instructed during the reproduction for 10 seconds, the microcomputer 11 instructs the second memory address control circuit 26 to jump to the first memory address of the next reproduction area. By doing so, skipping can be easily performed.

Embodiment 10 FIG.
FIG. 19 is a block circuit diagram of Embodiment 10 of the information reproducing apparatus of the present invention. In the tenth embodiment, it takes a certain amount of time to reproduce some information of all the disks. Therefore, if this is always performed when the power is turned on, the user has a long waiting time until the reproduction is started. If the disk is not replaced, the power supply of the microcomputer 11 and the second memory 25 is changed to the backup power supply 27 by utilizing the fact that the signal in the second memory 25 can be used as it is even if the power supply is once cut off. Back up with In addition, the changer mechanism 100 is provided with a disk detection switch 28 for detecting the replacement of each disk. The microcomputer 11 monitors the presence / absence of disk replacement by the disk detection switch 28 even when the main power supply (not shown) is shut off, and if any disk is replaced, a new one is turned on after the next main power supply is turned on. Control to play back some information of the disc only. Therefore, when there is no disk replacement, the waiting time of the user after turning on the main power supply can be eliminated, and the waiting time can be reduced even when only some of the disks are replaced.

  Of course, the device of the tenth embodiment can be applied to the eighth and ninth embodiments. In the above description, the signal stored in the second memory 25 is the first 10 seconds of the first song of each disk. However, the signal may not be the first song, and the signal may be not the first 10 seconds. It may be an appropriate amount of time during the process. However, in the eighth embodiment, since the disk change and the position search are performed while the signal in the second memory 25 is being output, the information needs to be the information for the first few seconds of each disk. In order to obtain a sufficient effect of reducing the silence time, a signal for a certain time or more is required.

  In the eighth to tenth embodiments, the first memory 23 and the second memory 25 have been described as being different from each other. However, the same functional operation is realized by using the same memory and controlling the memory address. Obviously you can. Further, it is obvious that the control according to the present invention can be realized without following the flowcharts of FIGS.

FIG. 2 is a circuit block diagram of the information reproducing apparatus according to the first embodiment of the present invention. FIG. 3 is a conceptual diagram of a data storage state in a buffer memory according to the first embodiment. 4 is a graph illustrating a relationship between a data amount in a buffer memory and a reference value E according to the first embodiment. FIG. 3 is a circuit block diagram of a write flag generation circuit according to the first embodiment. FIG. 9 is a circuit block diagram of an information reproducing apparatus according to a second embodiment of the present invention. FIG. 13 is a circuit block diagram of an information reproducing apparatus according to a third embodiment of the present invention. FIG. 13 is a circuit block diagram of an information reproducing apparatus according to a fourth embodiment of the present invention. 13 is a timing chart for stopping the disk drive between the information reproducing apparatus of the fourth embodiment and a conventional CD system. FIG. 14 is a circuit block diagram of an information reproducing apparatus according to a fifth embodiment of the present invention. 15 is a timing chart of the information reproducing apparatus according to the fifth embodiment. 15 is a timing chart of the information reproducing apparatus according to the second and fifth embodiments and a conventional CD system. FIG. 21 is a circuit block diagram of Embodiment 6 and Embodiment 7 of the information reproducing apparatus of the present invention. 33 is a timing chart of the information reproducing apparatuses of the sixth and fifth embodiments and a conventional CD system. FIG. 15 is a diagram illustrating an approximate output when the reproduction of the information reproducing apparatus according to the fourth to seventh embodiments is stopped. FIG. 21 is a circuit block diagram of an information reproducing apparatus according to an eighth embodiment of the present invention. FIG. 18 is a conceptual diagram of a second memory of the information reproducing device according to the eighth and ninth embodiments. 33 is a flowchart of the operation of the information reproducing device according to the eighth embodiment. Fig. 15 is a flowchart of an operation of the information reproducing apparatus according to the ninth embodiment of the present invention. FIG. 21 is a circuit block diagram of an information reproducing apparatus according to a tenth embodiment of the present invention. It is a circuit block diagram of the conventional MD system. 9 is a timing chart of a conventional MD system. It is a circuit block diagram of the conventional magazine type changer type CD player.

Explanation of reference numerals

  1 disk, 2 optical pickup, 3 reproduction amplifier, 4 demodulation circuit, 5 signal processing circuit, 9 digital output circuit, 11 microcomputer, 12 servo circuit, 13 disk motor, 14 key input, 15 display circuit, 16 buffer memory, 18 Address decoder, 20 end detection circuit, 22 memory data input / output circuit, 23 first memory, 24 first memory address control circuit, 25 second memory, 26 second memory address control circuit, 27 backup power supply, 28 Disk detection switch, 31 write address generation circuit, 32 read address generation circuit, 34 write flag generation circuit, 35 write control circuit, 44 data amount calculation arithmetic unit, 50 sub information extraction circuit, 51 register, 52 address correction circuit, 100 chain Jar mechanism.

Claims (1)

Means for detecting a signal level of reproduced information, an information reproducing apparatus for reading information recorded on a recording medium , temporarily storing the information in a memory, and reading and outputting the stored information from the memory; Means for judging the end of the reproduction target information when it is judged that it has fallen below a predetermined level, and when the information judged to be ended is stored in the memory, the drive of the recording medium is stopped and stored in the memory Control means for shifting to the next process before the output of the final information is completed .

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